ASP.NET Web API application and consume them using different types of a clients

For that first click on file new project

Select ASP.NET MVC 4 Web Application

Put a nice name

My

First

Web API

and say okay

And here is the ASP.NET MVC code project dialogue box

Select Web API and say okay

So here it is what we have Web API Project Template includes

a sample Web API called values with it.

If you are a ASP.NET MVC developer then you may find

lot's of features in Web API as similar to MVC

They are not exactly same

but

as a ASP.NET developer you can definitely views your knowledge here

but if you are not a ASP.NET MVC developer then

this things are going to be new for you

but it's not going to be difficult for you

Let's look at the some common features

In MVC we have something called as MVC controller

Whereas in Web API we have something called as API controller

The difference between these two controllers are

In API controller action methods are actually HTTP methods like Get, post,Put and Delete

Even we can overload these methods if required

We look into this method in details shortly but before that let's discuss about one more features i.e. Routes

Let's take a look at MVC default routes and try to understand how MVC request work

For that expand this app_start folder

We have route config.cs file here

open it

here it is MVC default routes

When request comes to MVC

it takes the URL and parses the first three segments of the URL

and the first segment is contoller

It find the class with this name

then we have action and it literally find the method inside this controller with this name

and we also have default or optional id parameter here

just like this in Web API

we have default Web API Routes

Just to keep it separate from MVC routes

Web API routes are prefix with the word API

we can change this name to anything like Invoice API,Customer API or may be facebook API

as per our requirement

then we have controller and we have optional id parameter

The beauty here is we don't have actions here

the reason behind that is action are actually HTTP methods

and depending on the type of client request for example

if it's a get request then get methods get called if it's a post request then post methods get called and so on

Let me close these both the files and move toward controller

What I will do is

I will put a break point here and exit to the application

okay

Now as per the route config I have to put API has prefix here and my controller name is values controller

So values and press enter

oh great breakpoint is here

If I press F5

I get the XML representation of my string array is it that simple

So let's look at the same request using Fiddler

For the those who don't know what is Fiddler is

Fiddler is a Web Debugging Tool which locks all HTTP traffic between our computer and the internet

it also let us make request and also let us modify the HTTP address as per our convenience

You can pause the video and copy the URL and download the fiddler to your computer

okay let me open fiddler

what I will do is

click on this composer tab

and we'll make a new get request to our Web API and click on a execute okay we get success message

Now let's look at the output we got

when we click on the raw what we can see here is

We are getting JSON representation of our string data

If you remember when we made the request using chrome we got XML representation where as in case of fiddler we are getting it as JSON

The reason behind that is we have something called as accept

Accept is a feeding HTTP header

It specify what kind of response a client can accept

Default

what we say

default accept value for chrome is XML whereas for fiddler it is

JSON

but

but in fiddler we can change that like this

Accept:application/acceptXML and say execute

okay we got a success

now if I click on raw what i can see

I am getting a XML representation of my string variable

If I click on compose

and change this XML back to JSON and click on execute what I can see I am again getting the JSON

This thing

this term is called as or this concept is called as content negotiation

depends on the client request server is returning the format

When client say I want XML it gives XML

When client say JSON it gives JSON

Even if we want we can written our own custom format like visiting card anything or image it may be anything

depends on the clients

depends on our requirement we can change the accept value and client

and if it is supported in the server it will return the same format

Now let's try to create something more interesting

First of all in this video we only talk about get method

we will try to cover post put and delete method in further coming videos

So let me remove this

okay

and let's create a small class called customer inside our model

And let's create two properties inside this

First one is int property called customer id

let make it i capital okay and let's create a second property a string property called customer name that's simple

Next we will move back to our controller i.e value controller

and just instead of returning this string what we will do is we will say he will written customer

say import

okay

and here I will say customer okay fine now I will say if i==1 than return

new customer customer id =1, customer name sukesh marla else

else

if i ==2 then return oh what happen oh sorry

its id

okay if i==2 then return new customer

customer id=2, customer name=new customer fine

okay or else I will return null okay simple

and again what we will do is

here we will write something like this new list of customer

here i will say this enter

and this okay

we are ready with our controller

we just created two get methods inside it

one returning list and second returning a single customer

now lets consume this web API

we will consume this Web API first using google chrome second using fiddler and third we will write JQuery and try to consume the same

So let's start with google chrome

what we will do is we will just run this application

okay

okay it's there

say /API/value okay we got it

we got the XML representation our list of customer

This is because entering a url and pressing enter

that mean we are actually making get request to our Web API

let me put break point here and run it again okay

see break point is getting hit here

when I say continue I am getting the XML okay

Now let me try with an another get method over loaded get method

okay where ever i put 1

I am getting Sukesh Marla in return

let me put breakpoint there

and let me try with second parameter say 2

I will press enter

okay it's there

say F10 okay

Id is not matching now id is matching we are getting new customer return okay that's it

We got the new customer here

If I parse something else other than 1 and 2

then I ma getting okay id is not matching again id is not matching I am getting null

okay we are getting nothing

that's it

It is that simple

we just consumed our Web API using google chrome

Now we will try the same using fiddler

for that let me launch fiddler once again

Fiddler is here let click on composer and let make a get request to our Web API

here is the Web API

and we got JSON representation of our list of customer now

If we change the except we did earlier

to application/xml and say execute

and if we check the result

here it is

we got the xml representation

Similarly we can make request to our another customer

another get method

and

output is here

in xml format

you can see we have sukesh marla is here

If you change the except I to JSON back

then we will get the result in JSON format

So it's that simple

we can use fiddler for the testing purpose

because we can test it for various format and all

Now the final demonstration where we will try to consume or Web API using JQuery

For that we have a small Web Application

called Web API test with us

with a simple button and a JQuery support

Here we have Jquery or Javascript Handller for the button and

our task is to write a code which will consume the Web API and display the result

So let's start coding

In Jquery we have something called as $.ajax which we can use to consume Web API

it has parameters

like url which will accept

which will take the Web API url

then we have type which will tell which kind of

Which method we are going to invoke

like get post or something else

next it has data type

what kind of format we are expecting in return

we expecting JSON for now

next we have a call back method called success

which get called when the result is return from web API

it has a parameter called data

Now let's start with

Okay what we will do is

we will put a alert and say data.customername

Now let's put a break point in our Web API

here and let's run this application

Now you notice as soon as if we click on this button we are getting break point here

If you notice the value of id is now 1

so definitely we are going to get this customer in return when I say F5 I am getting in alert sukesh marla which is because of

this code block

Similarly if we try to consume

previous get method which is going to return

list of customer then definitely we are suppose to make a loop on customers

we can do it like this

data, it has a function called as function key, customer then

what we have to do is we have to say alert

one we have customer.customer name then nothing that's it

Now if I press Ctrl F5 here

and try to click this button

I am getting sukesh marla and new customer as well

So here we finish our simple demonstration of how to create and consume ASP.NET Web API

hope you enjoyed

if you have any query you can write to us and we try to reply with the best possible way we can

Thank You